左旋多巴甲酯对斜视性弱视猫模型的作用

目的观察左旋多巴甲酯对斜视性弱视猫视皮质c-fos基因表达的影响,探讨盐酸左旋多巴甲酯对弱视的治疗作用及其作用机制。方法正常幼猫30只随机分成6组:左旋多巴甲酯低剂量、中剂量和高剂量组、模型对照组、阳性对照组及正常对照组,每组5只,于4wk时行眼外直肌切除术造成人工斜视(正常对照组除外),经图形视觉诱发电位(P-VEP)确定形成弱视后,灌胃给予左旋多巴甲酯20,40,80mg·kg-1,阳性对照组给予左旋多巴40mg·kg-1,正常对照组及模型组均给予等量生理盐水。观察P-VEP的变化并采用原位杂交技术检测各组猫视皮质的c-fosmRNA表达情况。结果左旋多巴甲酯明显的缩短猫斜视性弱视眼的P100波峰潜时及提高P100波幅值。斜视猫视皮质的阳性染色细胞较正常猫减少,差异有显著性(P<0.01),用药后各组阳性染色细胞较模型对照组明显增加(P<0.01)。结论左旋多巴甲酯明显地改善斜视性弱视猫模型弱视眼的传导和感觉功能,其机制可能与左旋多巴甲酯进入脑内的量增加及介导视皮质c-fos mRNA的表达调控有关。

Effects of L-dopa methyl ester on the strabismic amblyopia cats

Aim To observe the effects of the L-dopa methyl ester (LDME) on the pattern visual evoked potentials (P-VEP) and the expression of c-fos mRNA in neurons of the visual cortex of kittens with strabismic amblyopia, and explore the therapeutic effect of L-dopa methyl ester on amblyopia and its action mechanism.Methods 30 normal kittens were randomly divided into 6 groups: low dose of L-dopa methyl ester (20 mg·kg~(-1)), medium dose of L-dopa methyl ester (40 mg·kg~(-1)), and high dose of L-dopa methyl ester (80 mg·kg~(-1)),positive control (L-dopa 40 mg·kg~(-1)),normal control, and model control group.The surgery for producing iatrogenic convergent strabismus was performed on 4 weeks old kittens(normal control group excluded). After the confirmation of the development of amblyopia by pattern visual evoked potential,L-dopa methyl ester,L-dopa and normal saline were given to the corresponding animals, respectively. The P-VEP of amblyopia eyes was observed after one month, and the technique of in situ hybridization was used to detect the expression of c-fos mRNA.Results L-dopa methyl ester could reduce obviously the length of P100 peak latency of the cat strabismic amblyopes, and increase the amplitude of P100. The positive staining cells of strabismic cat visual cortex were less than those of normal cats, whose difference was significant (P<0.01).Positive staining cells in the treatment group were significantly increased when compared with that of the model group (P<0.01).Conclusion L-dopa methyl ester can significantly improve the conduction and sensory function in the model of strabismic amblyopia cats. The mechanism may be related to the increased amount of L-dopa methyl ester into the cerebral cortex and regulation of the expression of c-fos mRNA.